Improved fairing for an aircraft pylon, fairing arrangement, aircraft pylon and aircraft

Description

TECHNICAL FIELD

[0001] The present invention relates to an aircraft mast fairing, in particular an aircraft mast rear fairing. The invention relates more particularly to a mast fairing assembly comprising a fairing and elements for attaching the fairing to a primary structure of the aircraft, as well as to an aircraft mast comprising such a fairing assembly and an aircraft comprising such a mast. STATE OF THE PRIOR ART

[0002] Aircraft fairings are used in particular to provide aerodynamic surfaces to achieve good flight performance and reduce fuel consumption. Some fairings, including those arranged around an aircraft engine, are designed to withstand significant stresses. These stresses come, for example, from high temperature, significant vibrations, or the need for access to elements arranged behind the fairing. The rear fairings of aircraft struts, i.e. those covering the rear of an engine's attachment pylon (also called the engine pylon) are often considered to be secondary rear structures of the aircraft. In other words, they are attached to a primary structure of the aircraft and force transfers must be possible from the primary structure to these fairings, and vice versa.In order not to introduce unnecessary mechanical stresses, an isostatic assembly of the aircraft mast rear fairings is sought. Most often, the points of attachment of the fairing to the primary structure, also called interfaces, are doubled according to the known principle of . fail-safe, so that in the event of one of them breaking, the attachment point duplicating the damaged one can ensure the required load transfer. Indeed, the position of an aircraft pylon rear fairing makes it vulnerable in the event of a main landing gear tire burst. In this case, it is possible that two attachment points operating in duplicate could break simultaneously.

[0003] In addition, the attachment interfaces of these fairings are generally internal and require complex assembly operations during aircraft manufacturing or maintenance operations, or the presence of inspection hatches.

[0004] FR 2 964 947 A1 discloses an aircraft mast fairing extending along a longitudinal axis, and comprising a wall having at least two opposite flanks respectively oriented on either side relative to said longitudinal axis and a central interior cavity, the two opposite flanks meeting in the lower or upper part of said fairing, said fairing being such that it comprises: a front transverse rib securely fixed to said wall and extending perpendicularly on either side of said longitudinal axis, said front transverse rib comprising a through opening configured to receive a pin of an external structure by fitting in a direction parallel to said longitudinal axis and, a rear transverse rib securely fixed to said wall and extending perpendicularly on either side of said longitudinal axis.

[0005] The situation can be improved. STATEMENT OF THE INVENTION

[0006] An object of the present invention is to provide an aircraft mast fairing allowing isostatic assembly thanks to fixing points better protected in the event of a train tire bursting, easy to assemble from the outside, while limiting the number of parts to do so.

[0007] For this purpose, an aircraft mast fairing is proposed extending along a longitudinal axis, and comprising a wall having at least two opposite sides respectively oriented on either side relative to said longitudinal axis and a central interior cavity, the two opposite sides meeting in the lower or upper part of said fairing, said fairing comprising: a front transverse rib fixedly attached to said wall and extending perpendicularly on either side of said longitudinal axis, said front transverse rib comprising a through opening configured to receive a pin of an external structure by fitting in a direction parallel to said longitudinal axis, and comprising two yokes each having bores along a longitudinal axis oriented perpendicular to said longitudinal axis of the fairing and arranged opposite a through opening of one of said opposite sides, and, a rear transverse rib fixedly attached to said wall and extending perpendicularly on either side of said longitudinal axis and comprising two yokes each having bores along a longitudinal axis oriented perpendicular to said longitudinal axis of the fairing and arranged opposite a through opening of one of said opposite sides.

[0008] The invention also relates to a fairing assembly comprising an aircraft mast fairing as described above and four fixing elements configured to be inserted and held in position each in a bore of one of said yokes.

[0009] According to one embodiment, the aircraft mast comprises a fairing assembly as mentioned above and a primary aircraft structure, the primary aircraft structure comprising a pin oriented along an axis parallel to the longitudinal axis of the fairing and arranged to be inserted into the through opening of the front transverse rib, and four fittings respectively arranged to be inserted each into one of said yokes and each having a through opening configured to be arranged opposite the bore of said yoke and configured to receive a portion of one of said four fixing elements inserted into the bore of said yoke,the openings of the fittings intended to be inserted into the yokes of the front transverse rib of the fairing have an oblong shape extending in a direction perpendicular to the longitudinal axis of the fairing and said openings of the fittings intended to be inserted into the yokes of the rear transverse rib of said fairing have an oblong shape extending along an axis parallel to said longitudinal axis of said fairing, or vice versa.,

[0010] According to one embodiment, the openings of the fittings intended to be inserted into the yokes of the front transverse rib of said fairing have an oblong shape extending in a direction perpendicular to the longitudinal axis of the fairing and the openings of the fittings intended to be inserted into the yokes of the rear transverse rib of said fairing have an oblong shape extending along an axis parallel to said longitudinal axis of said fairing.

[0011] According to one embodiment, the openings of the fittings intended to be inserted into the yokes of the front transverse rib of said fairing have an oblong shape extending in a direction parallel to the longitudinal axis of the fairing and the openings of the fittings intended to be inserted into the yokes of the rear transverse rib of said fairing have an oblong shape extending along an axis perpendicular to said longitudinal axis of said fairing.

[0012] According to one embodiment, the pawn has a conical or truncated cone shape.

[0013] According to one embodiment, the fixing elements are countersunk screws and all or part of each of the bores of the aircraft mast yokes comprises an internal thread of a shape complementary to a thread of said countersunk screws.

[0014] According to one embodiment, only six mechanical connection interfaces are implemented between the primary structure and the fairing, the pin being doubled and the front transverse rib comprising a second through opening.

[0015] The invention also relates to an aircraft comprising a fairing as previously described, or a fairing assembly as mentioned above, or an aircraft mast as described above.

[0016] Finally, the invention relates to a method of assembling an aircraft mast as described above, the method comprising: a fitting of the fairing onto the pin of the primary structure of the aircraft mast, then, a positioning of the four yokes of the fairing around the four fittings of the primary structure so as to align the bores of the yokes with the oblong openings of the fittings, the fittings each being inserted into one of the yokes, then, an insertion of each of the four fixing elements into a bore of a yoke into which a fitting is inserted and into the oblong opening of the fitting, so as to maintain the fairing of the aircraft mast in position on the primary structure according to an isostatic equilibrium. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above-mentioned and other features of the invention will become more clearly apparent from the following description of an exemplary embodiment, said description being made in conjunction with the accompanying drawings: [ Fig. 1 ] schematically illustrates a powerplant assembled under an aircraft wing via a faired attachment mast; [ Fig. 2 ] schematically illustrates in perspective an aircraft fairing according to an embodiment positioned opposite a primary structural element; [ Fig. 3 ] is an enlargement of part of the Fig. 2 , illustrating a fairing positioning pin and a fairing attachment clevis; [ Fig. 4 ] is a sectional view schematically illustrating a front fairing attachment yoke and a fastening element configured for locking a primary structure fitting into the fairing attachment yoke; [ Fig. 5 ] is a sectional view schematically illustrating a rear fairing mounting yoke and a fastening element configured for locking a primary structure fitting into the fairing mounting yoke; [ Fig. 6 ] schematically illustrates an aircraft comprising a fairing according to one embodiment; [ Fig. 7 ] is a diagram illustrating a method of assembling an aircraft mast comprising a fairing according to one embodiment; and, [ Fig. 8 ] is a perspective section illustrating details of an attachment interface between a portion of an aircraft mast fairing and a primary structure, according to one embodiment. DETAILED PRESENTATION OF IMPLEMENTATION METHODS

[0018] There Fig. 1 illustrates an aircraft wing 1 under which a power unit 2 is assembled using an engine pylon 3. A front fairing 3' and a rear fairing 4 cover the engine pylon 3 in order to obtain good aerodynamic performance. The engine pylon 3 is an element of the primary structure of the aircraft, i.e. the "vital" structure of the aircraft, essential for flight. The fairings 3' and 4 are elements of the secondary structure of the aircraft. They contribute to improving the aerodynamic flight performance and reduce fuel consumption. In the present description, a direction X is defined as a direction in which the fuselage of the aircraft comprising the elements described in the Fig. 1 ; a Y direction is a transverse direction, perpendicular to the X direction and defining a horizontal plane with the X direction; and a Z direction is a vertically oriented direction, perpendicular to the X direction and perpendicular to the Y direction. Thus, the X, Y and Z directions define a reference right-angled trihedron and a movement of the aircraft in flight is carried out in the X direction when the flight is symmetrical (in the absence of skidding of the aircraft in the air). The engine pylon 3 comprises a fitting 30 on which is fixed a fixing support 31 carrying a pin 32, possibly doubled. These elements 30, 31 and 32, useful for fixing the fairing 4, are not shown on the Fig. 1 but visible on the Fig. 2 .

[0019] In the present description, the rear fairing 4 is referred to interchangeably as “fairing”, “rear fairing”, “engine mast fairing” or “secondary structure fairing”.

[0020] Furthermore, in this description, the term "front" means a part of a member facing or located on the side toward which the aircraft is moving in flight, and the term "rear" means a part of a member facing the side opposite the front, that is, on the side of the space left vacant by the aircraft moving in the air. Furthermore, in this description, the terms "bottom," "low," "lower," or "lower" mean a part of a part facing or located on the ground side when the aircraft is on the ground or operating normal flight in cruise at a stable altitude, and the terms "top," "high," "upper," or "upper" mean a part of a part facing or located on the sky side when the aircraft is on the ground or operating normal flight in cruise at a stable altitude.

[0021] There Fig. 2 represents the rear fairing 4 in a top perspective view, when it is positioned opposite the fitting 30 of the primary structure 3, carrying the pin support 31 on which the fairing positioning pin 32 is assembled. The fairing 4 is generally elongate in appearance, is in the form of a shell open in the upper part, and has a longitudinal axis 40a. A fairing wall 40 has two sides 401 and 40r opposite each other and respectively oriented towards the left crosswise and towards the right crosswise when the fairing 4 is assembled on the primary structure 3. According to one embodiment, the longitudinal axis 40a is parallel to the direction X when the fairing 4 is assembled on the primary structure 3 of the aircraft.Cleverly, the fairing 4 is assembled on the primary structure 3 by fitting the fairing positioning pin 32 into an opening 43 arranged in an ear of a front transverse rib 42 of the fairing 4, which rib 42 has a general U-shape, and by four fixing interfaces 4a, 4b, 4c and 4d arranged in the upper part of the fairing 4. According to one embodiment, the sides 401 and 40r meet to form a lower edge 40e in the lower part of the fairing 4. The front transverse rib 42 is fixed integrally to the fairing wall 40, and therefore to the sides 401 and 40r, and gives rigidity to the fairing 4. The front transverse rib 42, extending perpendicular to the longitudinal axis 40a, on either side on the other side of this, has two fairing fixing clevises 421 and 42r.According to one embodiment, the rib 42 has a general U-shape and each part of the rib 42 which extends on either side perpendicular to the longitudinal axis 40a is placed against a front part of one of the sides 401 and 40r of the fairing 4. According to alternative embodiments, the front transverse rib 42 can be solid or openwork. The yoke 421 is arranged at the end of the front transverse rib 42 located on the left cross-section side of the aircraft when the fairing is assembled on the primary structure 3 and the yoke 42r is arranged at the end of the front transverse rib 42 located on the right cross-section side of the aircraft when the fairing is assembled on the primary structure 3. Similarly, a rear transverse rib 44, held integral with the wall 40, and therefore with the sides 401 and 40r, extends transversely on either side of the longitudinal axis 40a and perpendicular to it.According to one embodiment, the rib 44 has a general U-shape and each part of the rib 44 which extends on either side perpendicular to the longitudinal axis 40a is supported on a rear part of one of the sides 401 and 40r of the fairing 4. According to alternative embodiments, the rear transverse rib 44 can be solid or perforated. Just like the front transverse rib 42, the rear transverse rib 44 provides rigidity to the fairing 4 and provides attachment interface points. To do this, yokes 441 and 44r are respectively arranged at the ends of the rear transverse rib 44.Advantageously, each of the fixing yokes 421, 42r, 441 and 44r is in the form of a U-shaped fitting comprising two arms in which a through bore is made, so as to be able to carry out a fixing of a fitting inserted between the two arms of the yoke and comprising a through opening, when this through opening is positioned in alignment with the bore made in the two arms of the yoke. Obviously, the through opening of a fitting configured to be fixed to the yoke is configured to receive a fixing element inserted into the bore of the yoke, or more precisely in each of the two bores respectively arranged in the two arms of the yoke, and aligned along the same central axis. The . Fig. 3 represents a part of the fairing 4 already shown on the Fig. 2 and enlarged to illustrate details of the pin 32 fitted into the opening 43 of the front transverse rib 42, as well as the yoke 421. Advantageously, the bore of the yoke 421 is made along a central axis 42a, perpendicular to the longitudinal axis 40a of the fairing 4. According to one embodiment, the pin 32 has a conical or truncated cone shape intended to facilitate the guidance of the fairing 4 relative to the pin 32 when fitting one onto the other. Fig. 4 represents a section along a YZ plane of the fixing yoke 421 forming a fixing interface with a fitting 33 of the primary structure 3. A bore 42b is made through the two arms of the yoke 421, along a central bore axis 42a. The fitting 33 of the fixing interface 4a comprises a bore 33' configured to receive a portion 46' of a countersunk screw 46 when the screw 46 having a thread 46' is screwed into the arm of the yoke 421 having a tapping 42a', complementary to the thread 46'. According to a preferred embodiment, the opening 33' of the fixing interface 4a (as well as that of the fixing interface 4b) has an oblong shape extending in the Z direction.The presence of an oblong shape advantageously makes it possible to maintain an isostatic balance of the assembly of the fairing 4 on the primary structure 3 since, as will be detailed later, the fittings 33 of the rear fixing interfaces arranged on the rear transverse rib 44 preferably have an oblong shape extending in the direction X. Obviously, the fixing element 46 may not be a screw, but any other fixing element configured to be inserted into the bore 42b of each of the clevis arms, to simultaneously pass through the oblong opening 33' when the fitting 33 is inserted into the clevis 421 and to be locked in position in order to avoid disassembly of the interface and loss of the fixing element 46.For example, the fixing element 46 may be a pin, or a key, the head of which has a smooth shape to provide surface continuity with the fairing 4 and the diameter of which allows for forced insertion in order to hold the fixing element 46 in position, once the latter is inserted into the yoke 421. Advantageously, this configuration makes it possible to fix the fairing from the outside of the fairing 4, substantially simplifying the assembly and disassembly operations, and making it possible to avoid having to implement inspection hatches in the fairing 4.The fairing attachment yoke 42r is made according to a similar principle, except that it is arranged symmetrically to the yoke 421 with respect to the longitudinal axis 40a, so as to allow, again, insertion of a fastening element 46 from the outside of the fairing, without requiring a complex operation during assembly and disassembly and without requiring inspection hatches in the fairing 4. According to one embodiment, the opening 33' of the fitting 33 configured to be inserted into the yoke 42r also has an oblong shape extending in the Z direction. Thus, the two openings 33' of the two fittings 33 configured to be respectively inserted into the yokes 421 and 42r of the front transverse rib 42 both have an oblong opening extending along the Z axis, so the width is equal to the diameter of bore 42b and therefore the length is greater than this. The . Fig. 5 illustrates the fixing yoke 441 arranged on the rear transverse rib 44. The yoke comprises two arms in which a bore 44b is made along a longitudinal axis 44a, perpendicular to the longitudinal axis 40a of the fairing 4. An internal thread (or tapping) 44a' allows the insertion of a fixing element 46 when the latter is implemented in the form of a screw, and holds the screw in position. Here again, the fixing element may be different from a screw, provided that it ensures that the fitting 33 configured to be inserted into the yoke 441 is held in position when the fairing 4 is in the nominal assembly position on the primary structure 3. The only notable difference with the fixing interfaces in which the yokes 421 and 42r participate is that a through opening 33" arranged in the fitting 33 preferably has an oblong shape extending in a direction X.The fixing yoke 44r is similar to the fixing yoke 441, except that it is arranged symmetrically to the latter with respect to the longitudinal axis 40a of the fairing 4, to allow insertion of a fixing element 46 from the outside of the fairing 4, without requiring a complex operation or an inspection hatch.

[0022] According to a preferred embodiment, the attachment interfaces 4a and 4b of the fairing 4 on the primary structure 3 therefore each have an oblong opening 33' which extends in the Z direction and the attachment interfaces 4c and 4d of the fairing 4 on the primary structure 3 each have an oblong opening 33' which extends in the X direction. This advantageously makes it possible to separate the main paths (or main directions) and the secondary paths (or secondary directions) for absorbing forces between the fairing 4 and the primary structure 3. More precisely, the main path for absorbing forces of the attachment interfaces 4a and 4b is operated in the X direction and the secondary path for absorbing forces of these same interfaces 4a and 4b is operated in the Y direction.According to a similar principle, the main path of force absorption of the fixing interfaces 4c and 4d is operated in the Z direction and the secondary path of force absorption of these same interfaces 4c and 4d is operated in the Y direction.

[0023] Finally, force transfers along the Y and Z directions, used as main force transfer paths, are operable via the fixing interface implemented by the pin 32 operating jointly with the opening 43 of the front transverse rib 42, possibly doubled by a second pin and a second opening to create a second fixing assembly (pin and opening) similar to the assembly formed by the pin 32 and the opening 43.

[0024] Advantageously, the main force-recovery paths described above contribute to an isostatic equilibrium of the attachment of the fairing 4 to the primary structure 3 and the secondary force-recovery paths are not activated under normal conditions of use (i.e. in the absence of abnormal physical constraints on the fairing 4 and / or the primary structure 3 which supports it). Advantageously, the fairing 4 has substantially lower rigidity characteristics along the secondary force-recovery paths than along the main force-recovery paths, so that the assembly of the fairing 4 on the primary structure 3 retains an isostatic character under normal conditions of use, but the secondary force-recovery paths can nevertheless be activated when a main force-recovery path is faulty or inoperative (due to at least partial rupture of a fixing interface).

[0025] According to an alternative embodiment, the through openings 33' of the yokes 421 and 42r of the front transverse rib 42 and the through openings 33" of the yokes 441 and 44r of the rear transverse rib 44 do not have oblong shapes, but bores whose diameter is at least equal to the diameter of the bore of the arms of the yoke in which the fitting 33 is inserted. This configuration is however not preferred, insofar as it leads to a hyperstatic equilibrium of the assembly, potentially likely to exert unnecessary mechanical stresses between the primary structure 3 and the fairing 4.

[0026] According to one embodiment, the pin 32 and the opening 43 of the front transverse rib 42 are both doubled to form a fail-safe fitting of a pin 32' and in an opening 43', if the first fitting should be defective or inoperative.

[0027] There Fig. 8 illustrates details of the fixing interface 4a already otherwise shown on the Fig. 2 , Fig. 3 et Fig. 4 The fixing element 46 keeps the fitting 33 fixed in position in the yoke 421 of the front transverse rib 42. This makes it possible to fix the front part of the sidewall 401 of the fairing 4 to the primary structure 3, which includes the fitting 33.

[0028] There Fig. 6 represents an aircraft 5 advantageously comprising a fairing 4. According to one embodiment, the fairing 4 constitutes, with four fixing elements 46, a fairing assembly 4 on the primary structure 3 (the engine pylon 3). The engine pylon 3 then advantageously comprises such a fixing assembly aimed at facilitating its assembly while preferably preserving an isostatic mounting of the fairing on the primary structure 3.

[0029] Advantageously, in the event of complete rupture of one of the attachment interfaces 4a, 4b, 4c or 4d between the aircraft mast fairing 4 and the primary structure 3, the attachment interfaces remaining intact make it possible to guarantee a good balance of the forces present on the aircraft mast fairing 4.

[0030] According to a preferred embodiment, the bores of the fixing yokes of the yokes 421, 42r, 441 and 44r are made around axes respectively oriented in the Y direction.

[0031] There Fig. 7 illustrates a method of assembling the fairing 4 on the primary structure of an aircraft, such as the aircraft 5. A step S0 is an assembly preparation step at the end of which the fairing and the primary structure are ready to be assembled by one or more assembly operators. During a step S1,the fairing 4 is brought closer to the primary structure 3 and in particular to the positioning pin 32. The opening 43 of the front transverse rib 42 is fitted onto the pin 32. Then, the fairing is positioned precisely during a step S2 so that each of the four fittings 33 is positioned so that its through opening 33' or 33", depending on whether it is a front or rear yoke, is aligned opposite the bore of the corresponding yoke. At the end of step S2, the positioning of the fairing 4 relative to the primary structure 3 and in particular to the fittings 33 of the primary structure 3 is such that it is possible to insert the four fixing elements 46. Finally, during a step S3, the fixing elements 46 are inserted into the bores of the four fixing yokes and locked in position. The assembly of the fairing 4 on the primary structure is advantageously easy and retains the advantages of isostatic equilibrium.

[0032] Furthermore, the presence of oblong through openings in the fittings 33 and extending respectively two by two in a direction X and in a direction Z makes it possible to carry out a transfer of forces in a main direction in the absence of a defect, in isostatic mode, then to carry out a transfer of forces in another direction, in the event of a defect in a fixing interface.

Claims

1. Aircraft pylon fairing (4) extending along a longitudinal axis (40a) and comprising a wall (40) having at least two opposite flanks (40r, 401) oriented respectively one on each side of said longitudinal axis (40a), and a central interior cavity, the two opposite flanks (40r, 401) meeting in the lower or upper part of said fairing (4), said fairing (4) being such that it comprises: - a front transverse rib (42) securely fixed to said wall (40) and extending perpendicularly on each side of said longitudinal axis (40a), said front transverse rib (42) comprising a through opening (43) configured to accept a peg (32) of an exterior structure (30, 31) by push-fitting in a direction (X) parallel to said longitudinal axis (40a), and comprising two yokes (421, 42r) each having bores along a longitudinal axis (42a) oriented perpendicular to said longitudinal axis (40a) of the fairing (4) and arranged facing a through opening in one of said opposing flanks (40r, 401), and - a rear transverse rib (44) securely fixed to said wall (40) and extending perpendicularly on each side of said longitudinal axis (40a) and comprising two yokes (441, 44r) each having bores along a longitudinal axis (44a) oriented perpendicular to said longitudinal axis (40a) of the fairing (4) and arranged facing a through opening in one of said opposing flanks (40r, 401).

2. Aircraft pylon fairing assembly comprising an aircraft pylon fairing (4) according to Claim 1 and four fixing elements (46) which are configured to each be inserted into and held in position in a bore of one of said yokes.

3. Aircraft pylon (3, 4) comprising a fairing assembly according to Claim 2 and an aircraft primary structure (3), said primary structure (3) comprising a peg (32) oriented along an axis parallel to the longitudinal axis (40a) of the fairing (4) and arranged to be inserted into said through opening (43) of said front transverse rib (42), and four fittings (33) which are respectively arranged in such a way as to each be inserted into one of said yokes (421, 42r, 441, 44r) and each having a through opening (33', 33") configured to be arranged facing said bore of said yoke and configured to receive a portion (46") of one of said four fixing elements (46) which is inserted into said bore (44b, 44b) of said yoke, said openings (33') in the fittings which are intended to be inserted into the yokes (421, 42r) of the front transverse rib (42) of said fairing (4) having an oblong shape extending in a direction perpendicular to the longitudinal axis (40a) of the fairing (4), and said openings in the fittings that are intended to be inserted into the yokes (441, 44r) of the rear transverse rib (44) of said fairing (4) having an oblong shape extending along an axis parallel to said longitudinal axis (40a) of said fairing (4), or vice versa.

4. Aircraft pylon according to Claim 3, wherein said openings in the fittings intended to be inserted into the yokes of the front transverse rib (42) of said fairing (4) have an oblong shape extending in a direction perpendicular to the longitudinal axis (40a) of the fairing (4), and said openings of the fittings intended to be inserted into the yokes of the rear transverse rib (44) of said fairing (4) have an oblong shape extending along an axis parallel to said longitudinal axis (40a) of said fairing (4).

5. Aircraft pylon according to Claim 3, wherein said openings in the fittings intended to be inserted into the yokes of the front transverse rib (42) of said fairing (4) have an oblong shape extending in a direction parallel to the longitudinal axis (40a) of the fairing (4), and said openings of the fittings intended to be inserted into the yokes of the rear transverse rib (44) of said fairing (4) have an oblong shape extending along an axis perpendicular to said longitudinal axis (40a) of said fairing (4).

6. Aircraft pylon according to one of Claims 3 to 5, wherein the peg (32) has a conical or frustoconical shape.

7. Aircraft pylon according to one of Claims 3 to 6, wherein the fixing elements (46) are countersunk screws and wherein all or part of each of said bores (42b, 44b) comprises an internal screw thread of a shape that complements a screw thread of said screws (46).

8. Aircraft pylon according to any one of Claims 3 to 7, comprising just six mechanical-connection interfaces between said primary structure (3) and the fairing (4), said peg being duplicated and said front transverse rib (42) comprising a second through opening.

9. Aircraft (5) comprising a fairing according to Claim 1 or a fairing assembly according to Claim 2 or an aircraft pylon according to one of Claims 3 to 8.

10. Method for assembling an aircraft pylon fairing according to one of Claims 3 to 8, the method comprising: - push-fitting the fairing (4) onto the peg (32) of the primary structure (3) of an aircraft pylon, then - positioning the four yokes (421, 42r, 441, 44r) of the fairing (4) around the four fittings (33) of the primary structure (3) in such a way as to align said bores (42b, 44b) of said yokes (42, 44) with said oblong openings (33', 33") of said fittings (33), said fittings (33) each being inserted into one of said yokes, then - inserting each of the four fixing elements (46) into a bore of a yoke (421, 42r, 441, 44r) into which a fitting (33) has been inserted and into the oblong opening in said fitting (33) so as to hold the fairing (4) of said aircraft pylon in position on said primary structure in a statically determinate manner.